Two physicists (a female and male) working on a lab experiment

ALP Seminar: Improved release-recapture thermometry with adaptive Bayesian techniques

25Apr
Seminars and colloquia
Time
Venue
Simpkins Lee
Beecroft Building
Seminar series
ALP seminar
Knowledge of physics?
Yes, knowledge of physics required
For more information contact

Abstract

The release–recapture method is extensively used to measure the temperature of ultracold atoms. Namely, the confining potential is switched off for a controlled time and the fraction of recaptured atoms is measured. Varying the release–recapture time allows to make a fit of the data to a theoretical model for the survival probability. Here, we process experimental data from potassium atoms in a tweezer trap with the newly introduced Bayesian framework of global quantum thermometry. We show that choosing the release–recapture time according to an adaptive Bayesian strategy, which maximises the information gain per measurement, substantially reduces the number of measurements needed to converge to an accurate temperature estimate. Furthermore, we show that the adaptive–Bayesian method produces much more reliable estimates, especially when data are scarce and noisy. By considering experimental imperfections in the loading of the tweezer and in the imaging step, we propose a 'plug-and-play' upgrade to any cold-atom experiment relying on release–recapture thermometry.